This application claims a priority based on Japanese Patent Application No. 2000-12809 filed on Jan. 21, 2000, the entire contents of which are incorporated herein by reference for all purposes.
The present invention relates to a technology for forming a moving picture obtained by photographing an object with a virtual camera, and displaying the moving picture on a display screen of a display device. The object moves in a virtual three dimensional field in accordance with manipulation contents conducted by a user, the manipulation contents being accepted via a controller.
Entertainment apparatuses such as a TV game machine, which is capable of performing a flight simulation and a drive simulation by the use of a three dimensional graphic animation, have been recently spread.
In this kind of entertainment apparatuses, a player controls an object representing an airplane, an automobile and the like by the use of a controller connected to the entertainment apparatus, and can allow the object to move in a virtual three dimensional field. This entertainment apparatus generates a moving picture obtained by photographing the object moving in this three dimensional field by the use of a virtual camera, and displays the moving picture on a display screen of a display device connected thereto.
Incidentally, in the conventional entertainment apparatus capable of performing the flight simulation and the drive simulation, the virtual camera is set at a position determined uniquely (fixedly) depending on a positional relation between the camera and the object.
FIGS. 15A and 15B are drawings for explaining a positional relation between an object (an object representing an airplane) 901 and a virtual camera 902 in this kind of conventional entertainment apparatus. Hereupon, FIG. 15A shows a state where the object 901 and the virtual camera 902, which are disposed in a three dimensional field, are overlooked just from above, that is, from an infinitely long distance of the Z-axis, and FIG. 15B shows a state where the object 901 and the virtual camera 902, which are disposed in the three dimensional field, are viewed just from the side, that is from an infinitely long distance of the X-axis. Note that illustrations of map constituent elements disposed in the three dimensional field are omitted in these drawings.
As illustrated in FIGS. 15A and 15B, in the conventional entertainment apparatus capable of performing the flight simulation and the drive simulation, the virtual camera 902 is set at a camera setup point A, that is, a position higher by a predetermined distance H than a position to the rear of the object 901 by a predetermined distance L. The camera setup point A is disposed above a line 903 passing through the object 901 along the moving direction of the object 901. Alternatively, the virtual camera 902 is set at a camera setup point B, that is, a position of the object 901. A sight line of the virtual camera 902 is settled so as to be pointed at an arbitrary point on the line 903 further in front of the object 901.
FIGS. 16A and 16B are schematic views showing a pictorial image obtained by photographing the object 901 by the use of the virtual camera 902, which is disposed as illustrated in FIGS. 15A and 15B. Here, FIG. 16A shows an example of the pictorial image obtained by the virtual camera 902 when the virtual camera 902 is set at the camera setup point A in FIGS. 15A and 15B, and FIG. 16B shows an example of the pictorial image obtained by the virtual camera 902 when this camera 902 is set at the cameral setup point B in FIGS. 15A and 15B.
In the conventional entertainment apparatus capable of performing the flight simulation and the drive simulation as described above, the virtual camera is set at the position determined uniquely (fixedly) depending on the relative position between the virtual camera and the object. Accordingly, the conventional entertainment apparatus has caused the following problems.
Specifically, in the actual world, when someone drives an automobile or pilots an airplane, he or she must pay attention generally to the broader and farther surroundings with an increase of a moving speed.
However, in the conventional entertainment apparatus capable of performing the flight simulation and the drive simulation as described above, since the setup position of the virtual camera is uniquely determined depending on the positional relation between the virtual camera and the object, the pictorial image surrounding the object, which is taken by the virtual camera, that is, which is displayed on the display screen of the display device, is constant regardless of the moving speed of the object in the virtual three dimensional field. For this reason, when the moving speed of the object is increased, the filed of vision of a player becomes narrower relatively, and hence a control of the object is prone to be extremely difficult for the player.
This problem might be solved in the following manner. Specifically, a moving speed determined by parameters entered by the player into a controller is not made to directly reflect on an actual moving speed of the object moving in the three dimensional field, but the object is allowed to move at a moving speed lower than that determined by the foregoing parameters in the three dimensional field. For example, the moving speed lower than the moving speed determined by the foregoing parameters is a value obtained by multiplying the moving speed determined by the parameters with a predetermined coefficient less than one. However, in this case, when the moving speed of the object moving in the three dimensional field is made to be extremely lower than the moving speed determined by the foregoing parameters, the player cannot acquire a desired feeling of speed from the moving picture displayed on the display screen of the display device, and cannot enjoy the simulation satisfactorily.
Accordingly, in an entertainment apparatus displaying a moving picture on a display screen of a display device, which is obtained by photographing an object moving in a virtual three dimensional field by the use of a virtual camera, the object of the present invention is to make it possible for a player to acquire a desired feeling of speed from the moving picture displayed on the display screen of the display device.
Furthermore, in an entertainment apparatus in which the player can control an object moving in a virtual three dimensional field by the use of a controller for a flight simulation and a drive simulation, another object of the present invention is to make it possible for the player to enjoy the control for the object satisfactorily. To be concrete, even when a moving speed of the object is increased, the present invention is to make it possible for the player to acquire a desired feeling of speed while preventing the control of the object from being extremely difficult.
To achieve the foregoing objects, in the entertainment apparatus of the present invention which forms the moving picture obtained by photographing the object (object representing, for example, an airplane and an automobile) moving in the virtual three dimensional field by the use of the virtual camera, and displays the moving picture on the display screen of the display device, a positional relation in the virtual three dimensional field between the object and the virtual camera is determined in consideration of the moving speed of the object in the three dimensional field.
For example, the positional relation is determined so that the virtual camera leaves the object far behind relative to the moving direction of the object as the moving speed of the object is more increased.
With such constitution, when the player increases the moving speed of the object by the use of the controller connected to the entertainment apparatus of the present invention, a pictorial image surrounding the object taken by the virtual camera broadens depending on an increase amount of the moving speed. In other words, the pictorial image surrounding the object, which is displayed on the display screen of the display device, broadens depending on the increase amount of the moving speed. Consequently, it is possible to solve the problem that when the moving speed of the object is increased, the control of the object becomes extremely difficult.
The moving speed of the object is reflected on the moving picture displayed on the display screen of the display device as a relative speed of the object for map constituent elements disposed around the object. Therefore, even when the pictorial image surrounding the object taken by the virtual camera broadens depending on the increase amount of the moving speed of the object, a feeling of speed acquired from the moving picture is not lost.
In the entertainment apparatus of the present invention, the camera setup means may settle a sight line direction of the virtual camera so that the virtual camera is pointed at a camera reference point that is a virtual point in the three dimensional filed, the camera reference point being settled in front of the object in the moving direction of the object.
For example, it is satisfactory that the camera reference point is settled so that the camera reference point moves further ahead in the moving direction of the object as a value related to the moving speed of the object becomes larger.
With such constitution, when the player increases the moving speed of the object by the use of the controller connected to the entertainment apparatus of the present invention, the pictorial image surrounding the object taken by the virtual camera, that is, displayed on the display screen of the display device, broadens far away depending on an increase amount of the moving speed.